// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CC_RASTER_STAGING_BUFFER_POOL_H_
#define CC_RASTER_STAGING_BUFFER_POOL_H_

#include <stdint.h>

#include <deque>
#include <memory>
#include <set>

#include "base/macros.h"
#include "base/memory/memory_coordinator_client.h"
#include "base/memory/weak_ptr.h"
#include "base/synchronization/lock.h"
#include "base/time/time.h"
#include "base/trace_event/memory_dump_provider.h"
#include "base/trace_event/trace_event.h"
#include "cc/output/context_provider.h"
#include "cc/resources/resource_provider.h"

namespace gpu {
namespace gles2 {
    class GLES2Interface;
}
}

namespace cc {
class Resource;

struct StagingBuffer {
    StagingBuffer(const gfx::Size& size, ResourceFormat format);
    ~StagingBuffer();

    void DestroyGLResources(gpu::gles2::GLES2Interface* gl);
    void OnMemoryDump(base::trace_event::ProcessMemoryDump* pmd,
        ResourceFormat format,
        bool is_free) const;

    const gfx::Size size;
    const ResourceFormat format;
    std::unique_ptr<gfx::GpuMemoryBuffer> gpu_memory_buffer;
    base::TimeTicks last_usage;
    unsigned texture_id;
    unsigned image_id;
    unsigned query_id;
    uint64_t content_id;
};

class CC_EXPORT StagingBufferPool
    : public base::trace_event::MemoryDumpProvider,
      public base::MemoryCoordinatorClient {
public:
    ~StagingBufferPool() final;

    StagingBufferPool(base::SequencedTaskRunner* task_runner,
        ContextProvider* worker_context_provider,
        ResourceProvider* resource_provider,
        bool use_partial_raster,
        int max_staging_buffer_usage_in_bytes);
    void RegisterMemoryCoordinatorClient();
    void Shutdown();

    // Overridden from base::trace_event::MemoryDumpProvider:
    bool OnMemoryDump(const base::trace_event::MemoryDumpArgs& args,
        base::trace_event::ProcessMemoryDump* pmd) override;

    std::unique_ptr<StagingBuffer> AcquireStagingBuffer(
        const Resource* resource,
        uint64_t previous_content_id);
    void ReleaseStagingBuffer(std::unique_ptr<StagingBuffer> staging_buffer);

private:
    void AddStagingBuffer(const StagingBuffer* staging_buffer,
        ResourceFormat format);
    void RemoveStagingBuffer(const StagingBuffer* staging_buffer);
    void MarkStagingBufferAsFree(const StagingBuffer* staging_buffer);
    void MarkStagingBufferAsBusy(const StagingBuffer* staging_buffer);

    base::TimeTicks GetUsageTimeForLRUBuffer();
    void ScheduleReduceMemoryUsage();
    void ReduceMemoryUsage();
    void ReleaseBuffersNotUsedSince(base::TimeTicks time);

    std::unique_ptr<base::trace_event::ConvertableToTraceFormat> StateAsValue()
        const;
    void StagingStateAsValueInto(
        base::trace_event::TracedValue* staging_state) const;

    // Overriden from base::MemoryCoordinatorClient.
    void OnMemoryStateChange(base::MemoryState state) override;

    scoped_refptr<base::SequencedTaskRunner> task_runner_;
    ContextProvider* const worker_context_provider_;
    ResourceProvider* const resource_provider_;
    const bool use_partial_raster_;

    mutable base::Lock lock_;
    // |lock_| must be acquired when accessing the following members.
    using StagingBufferSet = std::set<const StagingBuffer*>;
    StagingBufferSet buffers_;
    using StagingBufferDeque = std::deque<std::unique_ptr<StagingBuffer>>;
    StagingBufferDeque free_buffers_;
    StagingBufferDeque busy_buffers_;
    const int max_staging_buffer_usage_in_bytes_;
    int staging_buffer_usage_in_bytes_;
    int free_staging_buffer_usage_in_bytes_;
    const base::TimeDelta staging_buffer_expiration_delay_;
    bool reduce_memory_usage_pending_;
    base::Closure reduce_memory_usage_callback_;

    base::WeakPtrFactory<StagingBufferPool> weak_ptr_factory_;

    DISALLOW_COPY_AND_ASSIGN(StagingBufferPool);
};

} // namespace cc

#endif // CC_RASTER_STAGING_BUFFER_POOL_H_
